1. Field of the Invention
The present invention relates to a dynamo-electric machine such as a generator, and in particular, relates to a dynamo-electric machine wherein a coil end height of a stator may be reduced and which may be reduced in size.
2. Description of the Related Art
Generally, cooling ventilation is supplied to coil ends (bridge portions outside a stator core are called coil ends) of a statorxe2x80x94which are heat producing portionsxe2x80x94in order to realize compact high output in a dynamo-electric machine such as a generator and the like. In order to suppress wind noise due to ventilation at this location, it is necessary to reduce the size of the coils ends which are a ventilation drag. Hence, it is necessary to improve the space factor of electric conductors housed in the magnetic circuit of the stator and to line up and increase the density of bridge portions, i.e. coil ends, of the stator winding.
Constructions aimed at increasing the space factor of the electrical conductors using short conductor segments for the electrical conductors in the stator and at lining up and increasing the density of the coil ends have been proposed in Japanese Patent Application Laid-open No. Hei 11-164504, for example.
FIG. 21 is a side elevational view showing an enlarged portion of a coil end in a conventional dynamo-electric machine such as described in the above publication.
In FIG. 21, first extending portions 230b extending diagonally from slots 15a of a stator core 15 are drawn-out straight from the slots 15a of stator core 15. Also, turn portions 230a which are bent at respective locations and continuous with the first extending portions 230b are formed by bending relative to the first extending portions 230b. Furthermore, second extending portions 230c continuous with the turn portions 230a and leading to other slots are formed by bending relative to the turn portions 230a. The turn portions 230a are disposed so that surfaces including lateral surfaces thereof line up vertically with respect to end surfaces of the stator core 15. Constructing coil ends in this manner leads to stationary blade-type low noise at the turn portions 230a. 
In a conventional dynamo-electric machine such as described above there are problems in that, since the coil ends have a high axial height, electrical resistance is high, output is degraded and copper loss is increased, also, generating efficiency and temperature conditions are degraded. Moreover, though it is expected that a conventional coil end shape will have a stationary blade-like function, this location becomes a ventilation resistance, pressure loss increases and noise worsens.
The present invention aims to solve the above problems with the conventional art and an object of the present invention is to provide a dynamo-electric machine in which the height of coil ends in the axial direction may be reduced, it is possible to reduce the size, coil electrical resistance is decreased and output is increased, copper loss in the coil is decreased and temperature may be lowered and efficiency increased, and also, pressure loss at coil ends formed in ventilation passages may be lowered and noise may be suppressed.
In order to achieve the above objects, according to one aspect of the present invention, there is provided a dynamo-electric machine including:
a rotor including claw-shaped magnetic poles and fitted to a shaft;
a stator including:
a stator core disposed facing the rotor; and
a stator winding, a cross-section thereof being a flattened-shape, installed in the stator core;
a bracket supporting the rotor and the stator;
the stator core formed with a number of slots extending axially at a predetermined pitch in a circumferential direction,
the stator winding including a number of winding portions in which wire strands are wound so as to alternately occupy an inner layer and an outer layer in a slot depth direction within the slots at intervals of a predetermined number of slots, the wire strands folding back outside the slots at axial end surfaces of the stator core to form turn portions, and
the turn portions aligning in a circumferential direction to constitute coil end groups;
the coil ends including first extending portions extending diagonally from slots of the stator core, end portions formed by the turn portions being bent and continuous with the first extending portions, and second extending portions continuous with the turn portions and leading to other slots, each first and second extending portion being twisted around a respective extending direction axis and overlapping adjacent other first and second extending portions in a radial direction.
According to another aspect of the present invention, end portions formed by turn portions are inclined relative to a ray extending from a center of the stator core when viewed from an axial direction of the stator.
According to still another aspect of the present invention, end portions formed by turn portions are each inclined relative to the shaft when viewed from a radial direction.
According to still another aspect of the present invention, first and second extending portions are twisted as soon as they extend from the slots of the stator core.
According to still another aspect of the present invention, at least one portion of the first and second extending portions contacts adjacent other first and second extending portions.
According to still another aspect of the present invention, an outside diameter-side surface of the first extending portions of the stator winding forms an end-side surface as the turn portions and is bent around to form an inner diameter-side surface of the second extending portions.
According to still another aspect of the present invention, a cross-section of a coil of the first and second extending portions of the stator winding is thicker in a radial direction than in a circumferential direction.
According to yet another aspect of the present invention, a thickness of the coil end in a radial direction is approximately twice that of the wire strands of the first and second extending portions.
According to yet another aspect of the present invention, 2n strands of the wire strands are disposed in a row in the depth direction in each of the slots;
and the turn portions of the wire strands are arranged so as to align into n rows in a circumferential direction.
According to yet another aspect of the present invention, cooling means for supplying cooling ventilation inside the bracket by rotation of the rotor is further provided,
the coil ends being cooled by passage of the cooling ventilation inside the bracket.
According to yet another aspect of the present invention, the cooling ventilation passing through a ventilation passage is ventilated in a radial direction of the coil ends.
According to still yet another aspect of the present invention, the cooling means is a fan disposed at the rotor and the cooling ventilation is ventilated from an inner diameter-side of the coil ends to an outer diameter-side thereof.